Reinforced electrochemical energy storage through controlled construction of hierarchical hollow β-Ni(OH)2 microspheres enriched with oxygen vacancies induced by functionalized MWCNTs

Abstract

As promising electrode materials, hollow-structured metallic oxides/hydroxides have attracted extensive attention for their significantly enhanced catalyst and electrochemical performances. In practice, however, it is still challenging to construct well-dispersed hollow structures using facile and versatile template-free methods. And, as a result of the weak conductivity of most metallic oxides/hydroxides, it is a particularly effective means to integrate metallic oxides/hydroxides with carbon-based conductive substrates or introduce oxygen vacancies for further promoting reaction kinetics and achieving boosted electrochemical performance. Herein, a novel composite material consisting of oxygen-rich vacancy β-Ni(OH)2 coupled with oxidized multi-wall carbon nanotubes (Ov-Nβ/Cm) was synthesized using a one-step hydrothermal technique without the need for templates. The hierarchical hollow microsphere structure was achieved by utilizing oxidized multi-wall carbon nanotubes (MWCNTs) as an alternative to conventional surfactants or templates. The uniform distribution of multistage pores in the newly designed Ov-Nβ/Cm composite facilitates the transportation of electrolyte ions, thereby endowing it with outstanding electrochemical performance. A straightforward technique for producing high-quality Ni(OH)2-based electrode materials is presented in this investigation, along with fresh perspectives on the formation mechanism of hollow-structured composites. Developing MWCNT-based hollow nanostructured composites with oxygen vacancies-enriched will offer an essential novel avenue to exploit excellent electrode materials for supercapacitors and other energy storage systems.